Piston-stopper dispenser

ABSTRACT

A dispenser for a liquid cosmetic product, includes a reservoir, an internal piston, and an applicator end piece provided with and end valve. The dispenser is characterised in that the reservoir is defined inside the end piece, at a first end, by the valve, and, at the other end, by the piston, the piston forming a stopper screwed onto a threaded axial rod fixed to a base which is rotatably connected to the end piece.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/EP20041004834 filed on May 6, 2004, which designates the UnitedStates and claims priority of French Patent Application No. 0305667filed on May 7, 2003.

FIELD OF THE INVENTION

This invention relates to a dispenser of liquid cosmetic products aswell as to a method for packaging these products.

More specifically, the invention is applicable to products such as,particularly, creams, gels and semi-liquid viscous products, which arecurrently increasingly replacing traditional products in solid stick orpaste form.

BACKGROUND OF THE INVENTION

There are known dispensers of the type that comprise particularly areservoir, an internal piston and an applicator nozzle provided with anend valve.

For what relates, more specifically, to semi-liquid products, theirdensity and high viscosity render these dispensers useless and make itnecessary to modify their structure in order to meet stricter conditionsof dosing, watertightness and protection of the product.

For marketing reasons, it is equally important to preserve at least partof the overall appearance of the traditional packaging in order to avoidan abrupt break with the make-up habits of the users.

In particular, it seems essential to perpetuate the use of a rotarymovement for delivering and dosing the product.

And yet, due to the fluidity of certain products, resorting to such amovement poses watertightness and dosing problems.

It is necessary particularly to guarantee hermetic blocking of thedispenser using an end valve that does not have any kind of retentionarea in which a residual volume of the product would be at a risk ofremaining and drying up, resulting in blocking the valve.

Furthermore, the packaging of liquid cosmetics poses specific problemsrelating particularly to the air contained in the reservoir, which mustnecessarily be evacuated during the filling phase of the dispenser.

This hydraulic constraint generally implies implementing complex meansat the product manufacturer's plant, which result in parasitic technicaldifficulties and pointless additional costs.

SUMMARY OF THE INVENTION

The aim of this invention is to solve these problems in a satisfactorymanner, by providing a dispenser with an original structure using thepiston-plug concept.

This aim is achieved, according to the invention, by means of adispenser characterised in that the said reservoir is delimited insidethe nozzle, at a first end by the said valve and, at the other end, bythe said piston forming a plug, which is screwed onto a threaded axialrod formed integral with a base connected rotatingly to the said nozzle.

According to an advantageous characteristic, the said piston comprises,on the one hand, a cylindrical compression element covering the saidthreaded rod and having a peripheral lip in watertight contact with theinside wall of the reservoir and, on the other hand, on the outside ofthe said reservoir, a connection collar attached to the said rod androtatingly blocked on the said base.

According to an alternative embodiment of the invention, the saidreservoir is provided with a jacket fixed in the nozzle extended, ifrequired, by a sleeve housed in the base.

Preferably, the said sleeve is provided with means for blocking therotation of the said piston and means for locking it in the base.

Another aim of the invention is a method for packaging a liquid cosmeticproduct in a dispenser of the type comprising, particularly, anapplicator nozzle enclosing an internal piston and a reservoir blockedat a first end by a valve, characterised in that the reservoir is filledby its other end in the inverted position of the dispenser, and then thesaid piston is inserted as a plug, expelling the air in the reservoir toclose off this other end in a watertight manner, and the piston islocked in this closed position.

According to an advantageous characteristic of the method, it providesfor a threaded axial rod, formed integral with a base, to be insertedand fixed in the said piston, prior to closing the reservoir.

Furthermore, the fixing of the rod in the piston and transmission of themovement are provided by elastic distortion of the material from whichthe piston is made.

In addition, the piston is locked in the closed position of thereservoir by axially and rotatingly connecting the base to the nozzle.

In parallel, the rotation of the said piston is blocked by cooperationwith limit stops formed integral with the nozzle.

Preferably, the watertightness of the reservoir is only ensured whenlocking the said piston.

Finally, the reservoir is filled leaving a small amount of air forming abuffer such as to prevent the product from leaking through the valvewhen inserting the piston.

Thus, the rotation movement of the base is transformed into an axialtranslation of the piston in the reservoir, which places the productunder pressure and enables it to be delivered.

The dispenser of the invention has a general appearance and ergonomicsthat are very similar to those of traditional sticks while having verydifferent functional elements that are adapted to the nature of newsemi-liquid products, to their physical properties and to the smalldoses that need to be dispensed.

This dispenser can therefore have applications in the field of liquidcosmetics, packaged for sale or as samples.

In addition, the watertightness of the dispenser and the way in whichthe product is dispensed are perfectly compatible with the constraintsthat relate to liquid cosmetic products.

The dispenser of the invention also has a very simple structure andtherefore a particularly inexpensive cost price.

Moreover, the packaging method of the invention is particularly easy toimplement and its piston-plug principle provides watertight and reliablesealing of the dispenser, which overcomes the problems of air beingincluded.

In fact, the air is released gradually during the blocking phase as thepiston enters the reservoir.

In addition, there is no need to provide watertightness means at thebottom of the dispenser insofar as the piston-plug already provides thiswatertightness inside it, at the top.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from reading the followingdescription made in reference to the appended diagrams, in which:

FIG. 1 shows an axial section view of an embodiment of the dispenser ofthe invention.

FIGS. 2A to 2C show schematic views of various steps in the packagingmethod of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The dispenser shown in FIG. 1 is designed for delivering and applyingliquid cosmetic products.

For this purpose, it comprises an applicator nozzle 1 provided with anend valve 2, a product reservoir 10 and an internal piston 3.

The valve 2 is made up, for example, of an evacuation orifice 20arranged on an elastically distortable portion of the wall of the nozzle1, with its edges resting against a pin or needle valve 50 supportedhere, via a spacer 55, by a jacket 5 fixed in the said nozzle.

According to an alternative not shown in the figures, it is possible toadd a lid to cover the nozzle 1, which can support the pin instead ofthe jacket, if required.

The reservoir 10 is delimited inside the nozzle 1, at a first end (topin this case) by the valve 2 and, at the other end (bottom in this case)by the piston 3 forming a plug, which is screwed onto a threaded axialrod 41 formed integral with a base 4 rotatingly connected to the nozzle1.

The piston 3 comprises a cylindrical compression element 31 that coversthe threaded rod 41 and has a peripheral lip 35 that is able to slide inwatertight contact with the inside wall of the reservoir 10, in thiscase covered with the jacket 5.

This compression element 31 is connected, outside the reservoir, via asocket 33, to a connection collar 32 attached to the rod 41 androtatingly blocked in the base 4 by means of limit stops formed integralwith the nozzle 1, such as a series of axial ribs 42.

Preferably, as shown in the figures, the jacket 5 is extended by asleeve 54 that is housed and axially locked in the base 4, for exampleusing locking means 44 that allow the relative rotation of the latter.

The jacket 5 matches the inside profile of the nozzle 1 and has awidened section 53 for connection with the sleeve 54.

Rotating the base 4 in relation to the nozzle 1 results, by transmissionof the movement via the thread and the limit stops 42, in ascendingaxial translation of the piston 3 inside the reservoir 10 and thenecessary compression of the product, forcing the valve 2 to open anddeliver the product.

The assembly of the various parts of the dispenser as well as thepackaging of the product are carried out as follows, placing the nozzlein an inverted position as shown in FIGS. 2A to 2C.

First of all, the reservoir 10 is filled by the open end of the sleeve54, the valve 2 remaining closed and providing the watertightness at thebottom as shown in FIG. 2A.

The filling of the reservoir stops when the level of the product Preaches, at maximum, the widened section 53 of the sleeve 5.

It is preferable, however, to leave a small amount of air above thelevel of the product in order to compensate for possible faults in thefilling and/or in the positioning of the piston 3 and to avoid the riskof the product leaking out of the valve 2 when inserting the piston.This layout makes it possible to create a compressible area forming abuffer that is able to absorb the pushing effort of the piston and tominimise its effects on the uncompressible liquid product.

The base 4 is assembled on the piston 3, previously or on the packagingsite, by forced insertion of the rod 41 in the collar 32 as shown inFIG. 2B.

If the collar is not provided with a thread, it must be made from aflexible, elastic material that allows it to distort in order to fix andanchor on the threads of the rod 41, which in turn is made from a rigidplastic material.

Then, the piston 3 is inserted in the jacket 5 as if it were a plug,pushing by the base 4 and expelling, via the lip 35 and around thesocket 33, the air contained in the reservoir.

In the final phase of the assembly operations, the fraction of air thatremains inside the reservoir, is expelled to the outside, under theincreasing pressure created by the piston, passing through the gorge 34made in the wall of the collar 32, getting round the edge of the sleeve54 and then through the evacuation channel 40 made in the wall of thebase 4 or, according to an alternative, through a groove (not shown)made in the outside wall of the sleeve 54 or in the inside wall of thebase.

Therefore, only the lip 35 reaches the end, in watertight contact withthe wall of the sleeve 5 at the height of the section 53.

Thus, the reservoir 10 is only sealed in a watertight manner during thefinal step, when the piston-plug 3 is locked in its blocking position byaxially connecting the base 4 to the socket 54 of the nozzle.

The rotation of the piston 3 is also blocked at this point bycooperation of the collar 32 with the limit stops 42 formed integralwith the socket 54 and thus with the nozzle 1.

In this position, the compression element 31 is almost in contact withthe free surface of the liquid product P and, once returned to theposition shown in FIG. 1, the dispenser is ready to be used.

The axial movement of the piston 3 in the reservoir, in the direction ofthe valve, causes compression inside the reservoir 10 and a depressionin the compartment delimited between the base 4, the sleeve 54, thesocket 33 and the collar 32. This depression is compensated by air beingtaken in through the channel 40 and the gorge 34.

Thus, the watertightness of the dispenser is only necessary at the levelof the piston-plug, which thus forms, during operation, the bottom ofthe reservoir 10.

A tamper-proof strip placed between the nozzle and the base canadvantageously complete the assembly while a lid (not shown) can, ifrequired, round off the packaging and the aesthetic appearance of thewhole dispenser.

1. A dispenser for liquid cosmetic products comprising a reservoir, aninternal piston and an applicator nozzle provided with an end valve,characterised in that said reservoir is delimited inside the nozzle, ata first end, by said valve and, at the other end, by said piston forminga plug, which is screwed onto a threaded axial rod formed integral witha base rotatingly connected to said nozzle.
 2. A dispenser according toclaim 1, characterised in that said piston comprises, on the one hand, acylindrical compression element covering said threaded rod and which hasa peripheral lip in watertight contact with the inside wall of thereservoir and, on the other hand, on the outside of said reservoir, aconnecting collar attached to said rod and rotatingly blocked in saidbase.
 3. A dispenser according to claim 1, characterised in that saidreservoir is provided with a jacket fixed in the nozzle which isextended, as required, by a sleeve housed in the base.
 4. A dispenseraccording to claim 3, characterised in that said sleeve is provided withmeans for blocking the rotation of said piston and means for axiallocking in the base.
 5. A method for packaging a liquid cosmetic productin a dispenser of the type that comprises an applicator nozzle,enclosing an internal piston and a reservoir blocked at a first end by avalve, characterised in that the reservoir is filled by its other end,with the dispenser in its inverted position, and then the piston isinserted in the form of a plug, expelling the air contained in thereservoir in order to close off this other end in a watertight manner,and said piston is locked in this closed position.
 6. A method accordingto claim 5, characterised in that, prior to closing the reservoir, anaxial rod formed integral with a base is inserted and fixed in saidpiston.
 7. A method according to claim 6, characterised in that thefixing of the rod in the piston and the transmission of the movement areprovided by elastic distortion of the material from which the piston ismade.
 8. A method according to claim 5, characterised in that the pistonis locked in the closed position of the reservoir by axially androtatingly connecting the base to the nozzle.
 9. A method according toclaim 5, characterised in that said piston is rotatingly blocked bycooperation with limit stops formed integral with the nozzle.
 10. Amethod according to claim 5, characterised in that the watertightness ofthe reservoir is only ensured during the step in which said piston islocked.
 11. A method according to claim 5, characterised in that thereservoir is filled leaving a small amount of air inside it forming abuffer in order to avoid any leaks from the valve when inserting thepiston.